New Grower Mephisto, Megacrop in soil and autopots (Skywalker, 3BOG, Sour Stomper, and 2 Illuminautos)

[Big Sul]

Been using this regarding VPD. I am still learning about it. To continue w/KISS model I just keep it in the green. Is that correct?

 

[terp182]

Here’s the site that page was from, which I’ve been using, yes.

Vapor Pressure Deficit - The Ultimate Guide - Dimlux Lighting - The Best Grow Lights

Simply put, Vapor Pressure Deficit measures the difference between the amount of drying power the atmosphere is exerting upon your plants. VPD is the key...

www.dimluxlighting.com

If you look at the key on the top right, Green is for seedling/early veg. I’m targeting blue right now in early flower. Also important to note is your jpg has the chart for -1 degree leaf temp to room temp adjustment (True VPD is measured by leaf temp, so those room temp charts are useful if you know how much cooler your plant leaf temps are than your room temp.) My offset is 3 degrees, so I use that chart on the site. But yeah, the goal is to keep the temp/RH combo in the right color, depending on stage, to optimize growth from a temp/humidity perspective.

 

[WildBill]

The plants are all finally in flower, and now controlling RH is my main focus. The fan will go up to 8 trying to keep it down to 60%, and the leaf temps are around 69-71. It’s tough because the humidity outside is >75%.

Should I just get a dehumidifier for the room the tent is in? I don’t like being out of ideal VPD range and it might cost less to run the dehumidifier than to keep the tent fan on high trying time keep it just at 60%. I’ve also done a couple rounds of defoliation, just focusing on lower leaves getting no light, lower suckers, and upper leaves blocking light.

Otherwise, everything looks great with the girls. I’m trying to figure out whether to supplement with Recharge over in the “Dialing in MC” thread, but otherwise the plan is to keep it simple, resist the urge to tinker and fuck it up, and let them grow unimpeded.

Any insight on managing RH through flower (like, what RH should I realistically be happy with?) would be much appreciated!

Also - two SP-3000’s in a 4x4 is more than enough coverage. I can’t turn them up over 70% at 22+ inches without seeing light burn at the tips. This is not a complaint - I’m happy to have head room with the light wattage and know that isn’t the bottleneck in growth! But for anyone with SP-3000’s, go easy and back off the canopy with them.

Oh boohoo! You have TWO SP3000s and can't turn 'en up!! LOL!

That's what I wanted for this winter grow!
In a 4X4, that's one even light coverage

75%! Damn! I forgot where are you? Winter? Cold?
What's the ancient room temp?
The dehumidifier is gonna heat things up for sure.
So you should really try to mount your drivers outside the tents. That's a pretty big heat load in the tent. But try some thing before you move them. Mine is easy, but I planned on doing that from the begininng.
To be honest, I'd go ahead and get a dehumidifier. I did! It will be easier to dial your VPD.
You do need to ask yourself is it worth getting it. How many months out of the year do I have high Rh. Don't get a cheap one and they can be noisy!
Ya haven gone cheap on the grow and ya have a great grow going. Look at the value in canna that you could get if you finish this out getting close to a good VPD.

 

[WildBill]

Been using this regarding VPD. I am still learning about it. To continue w/KISS model I just keep it in the green. Is that correct?

The colors denote the life stage of the plant. You follow the color of the stage your girl is in.

 

[terp182]

Oh boohoo! You have TWO SP3000s and can't turn 'en up!! LOL!

That's what I wanted for this winter grow!
In a 4X4, that's one even light coverage

75%! Damn! I forgot where are you? Winter? Cold?
What's the ancient room temp?
The dehumidifier is gonna heat things up for sure.
So you should really try to mount your drivers outside the tents. That's a pretty big heat load in the tent. But try some thing before you move them. Mine is easy, but I planned on doing that from the begininng.
To be honest, I'd go ahead and get a dehumidifier. I did! It will be easier to dial your VPD.
You do need to ask yourself is it worth getting it. How many months out of the year do I have high Rh. Don't get a cheap one and they can be noisy!
Ya haven gone cheap on the grow and ya have a great grow going. Look at the value in canna that you could get if you finish this out getting close to a good VPD.

I know, I know, good problems to have with the lights. I just kept burning the tips a little, and it definitely wasn't the nutes, but I'm happy to turn them back down a little.

I'm in the PNW, near Seattle. Ambient room temp is 69-70. So a dehumidifier is gonna be needed, it's clear. Thanks for the advice. I don't like the texture of the leaves even right now, so it's kind of a no brainer but I'm glad you validated it. From what I've heard, it's better to do the room than the tent itself, so that's the plan. Couldn't be happier with the grow otherwise!

 

[WildBill]

I know, I know, good problems to have with the lights. I just kept burning the tips a little, and it definitely wasn't the nutes, but I'm happy to turn them back down a little.

I'm in the PNW, near Seattle. Ambient room temp is 69-70. So a dehumidifier is gonna be needed, it's clear. Thanks for the advice. I don't like the texture of the leaves even right now, so it's kind of a no brainer but I'm glad you validated it. From what I've heard, it's better to do the room than the tent itself, so that's the plan. Couldn't be happier with the grow otherwise!

LOL! Seattle area? You didn't ask for validation! You knew you needed a humidifier. You wanted a kick in the butt to just go buy it! LOL!

 

[terp182]

LOL Alright, you're not wrong. For some reason I was really dragging ass on dropping that couple hundo. Painful, it was. Re-reading my comment, "Yeah I'm in Seattle - dehumidifier??", I realize how smart I sounded.

So I went and got one of those portable AC units/dehumidifiers off of OfferUp. Seems to work just fine, and right now I don't even need to vent it outside. The VPD is right near the sweet spot of 55ish RH and 73-75ish leaf temp, and it seems like moving the blower end nearer to the tent will help manually adjust RH in there a bit, since the unit doesn't adjust for it automatically (d'oh). But I figured the A/C could work with a Cold Bot down the line in the tent to perhaps substitute for a freeze dryer for a certain application, so it's worth losing that piece of automation and it's gonna run constantly anyway. I'd love to hear thoughts/experience with using ACs in tents to dry bubble hash if anyone has any, incidentally.

Now that I have the second MarsHydro SP-3000 up and running, I think I found the issue with the first one. I could be wrong, and probably am, but it seems like the dimmer dial on the first one isn't accurate, setting the light to 100% power when its set below 75. Initially, I thought I just couldn't tell the difference in intensity with my eyes (no PAR meter, sadly but I watched the Apogee guy's video explaining how bad our eyes are at detecting light intensity), but after getting the second SP-3000, its dimmer works as it should, I can see a clear difference between 75 and 100, and the plants aren't getting leaf burned at the prescribed settings (i.e. 75% at 20"). So now, I've got the first SP-3000 in the back set to 50% at 24". Whatever works. The back plants seem much happier, and this explains all the light stress I had in my first grow though. I'll get back and confirm when I can find a PAR or kill-a-watt meter.

Other than that Encyclopedia Brown-ing, the girls continue to rise ascendant, on Day 39/38. I'm pretty sure the Sour Stomper isn't flowering yet, somehow. Following from the Dialing in MegaCrop thread, I kicked up the nutes to 585/6.4 and I can see a slightly darker leaf in the new growth, but they're taking it fine. I also got the Recharge in the mail today, but I'm going to hold off on that since I just increased the PPM. Seeing zero issues with nute uptake so it's not a priority, unless for some reason I'm missing it should be? I've also super cropped very selectively to even out the canopy, with those little plastic clips. Other than that, I think everything is dialed in pretty nicely for now!

Pictures below. The tent is filled, and the light to the Solo cup Sweet n' Smelly bansai I'm working on for the lady is about to be drowned out by other plants' growth. Another one of them good problems. My goal the next 4 or so weeks is to stay out of the way, manage VPD and nutes (the MegaCrop does tend to have the pH creep up a tenth of a point every other day), and see what these girls can show us on straight MegaCrop with a nearly dialed in environment. Let's goooo!

 

[Big Sul]

Thx for insight into ur thought process. It really helps me analyze needs & unintended consequences. I also giggle how u & I have similar issues, BUT on the opposite end of the scale. As u are in PNW, I am In SW desert. My issues are maintaining rh in VPD. I know in another month or 2, I'm going to be battling higher temps, so I am looking into if I need AC or if I can maintain via ventilation.

 

[WildBill]

Thx for insight into ur thought process. It really helps me analyze needs & unintended consequences. I also giggle how u & I have similar issues, BUT on the opposite end of the scale. As u are in PNW, I am In SW desert. My issues are maintaining rh in VPD. I know in another month or 2, I'm going to be battling higher temps, so I am looking into if I need AC or if I can maintain via ventilation.

It's gonna be hard. Is your grow in the house or garage?

 

[Big Sul]

It's gonna be hard. Is your grow in the house or garage?

Garage. It's a work in progress. Switching to 20-4 lighting vice 24-0. Also have more frequent exhaust cycles at my disposal. Currently have exhaust every 3 hrs. Considering switching to exhaust every hour for 15 min. However, I'm only making 1 change at a time to determine its impact. Currently not out of parameters, but trying to foresee issues coming.